exam 3 Flashcards
where does glycogenolysis occur
muscle and liver
glycogenolysis in the liver serves what purpose
to maintain blood glucose homeostasis
what does glycogenolysis in the muscle serve for
providing glucose as a substrate for ATP production in the muscle cell
what is the first line of defense for blood glucose maintenence
glycogen
cleaves α-1-4-glycosidic bonds
from non-reducing ends
glycogen phosphorylase
will remove 3 of last 4 glucosyl units
above branch, attaching them
via α-1-4-glycosidic bonds to a
nearby linear branch
debranching enzyme
Is Glycogen phosphorylase active when phosphorylated
yes
which enzyme phosphorylates Glycogen phosphorylase
GPK
protein kinase A (PKA) activates which enzyme
GPK
glycogen phosphorylase is dephosphorylated by which enzyme
PP1
in the liver, glucose is a negative regulator of _________
GP-P
AMP is a ___________ allosteric regulator of GP (non-phosphorylated form) in skeletal muscle
positive (activator)
Pi is a ________________ regulator of both GP-P and GP (non-phosphorylated) forms
positive allosteric
_________ is a negative (inhibitor) allosteric regulator of both GP-P and GP (non-phosphorylated) forms in skeletal muscle
Glucose-6-phosphate
does acetylation of GP-P increase or decrease its activity
decrease
refers to the
process by which body proteins are
continually degraded and re-
synthesized
protein turnover
Truer or false, collagen and hemoglobin are resistant to degradation
true
where in a cell is the Ubiquitin-proteasome
pathway located
cytoplasm and nucleus
the Autophagy-lysosomal system is only present in the ___________
cytoplasm
Mainly responsible for degrading longer-lived proteins and entire organelles
Autophagy-lysosomal system
essential organelle for mTOR signaling
lysosome
Primary control of cell growth
mTor
Directly binds and activates mTORC1
Rheb GTPase
__________ translocates mTORC1 to lysosomal surface
GTP loaded RagA
____________ inactivates mTORC1 and translocates back to the cytosol
RagA-GDP
Inhibits Rheb GTPase
Tuberous sclerosis complex
inhibited by AKT phosphorylation
TSC
Low AMP _________ protein synthesis but _________ degradation
stimulates; inhibits
protein synthesis pathways are
most active over the first _____ hours after a meal
4
_________ activates mTOR
insulin
become the most abundant lipoproteins in the blood
stream
VLDL and LDL
The process by which glucose is made in the liver, and to small extent kidneys, from non-carbohydrate carbons sources
gluconeogenesis
become the predominant substrate for ATP production in
cells that have mitochondria
fatty acids
becomes more prominent with long-
term fasting and starvation
protein degradation
this hormone is Produced in alpha cells of
pancreas
glucagon
Insulin leads to dephosphorylation of PFK2, _________ F2,6 BP levels
increasing
is GNG energetically expensive
yes
substrates for gng
AAs, glycerol, lactate
lipolysis is most active
during the _________
state
fasted
alanine becoming a more
prominent substrate for GNG is what cycle
Glucose-Alanine Cycle
substrate for
GNG becomes more
prominent during exercise
lactate
gng prominent substrate during prolonged fasting and starvation
AAs
Hydrolyzes TAGs to liberate 1 FA and 1 diacylglycerol (DAG)
Adipose triacylglycerol lipase
Hydrolyzes DAGs to liberate 1 FA and 1 monoacylglycerol
Hormone sensitive lipase
Hydrolyzes MAG to liberate 1 FA and 1 glycerol
Monoacylglycerol lipase
When CGI-58 bound to perilipin, lipolysis is
______ active
less
Removes carnitine and adds back CoA
CPT2
Transports fatty acyl carnitine across mitochondrial membrane
Carnitine acyl translocase
Removes CoA and replaces with carnitine
CPT1
where does beta oxidation take place
mitochondrial matrix
when are ketones formed
Prolonged fasting/starvation, >24hours through
starvation conditions
* Very low carbohydrate diets
* During prolonged exercise without replenishment of
carbohydrates
* Uncontrolled diabetes
Any cells with __________ can utilize ketones for ATP instead of
glucose
mitochondria
cholesterol
synthesis take place in the
cytosol
Ketones can cross the blood brain barrier, true or false
true
how do we measure ketones
urine test, serum, finger stick
normal range of ketones is
0-25mmol/l
Occurs in the mitochondria and cytosol of periportal
hepatocytes
urea cycle
primary system that makes urea via the Urea Cycle
periportal hepatocytes
α-amino group from an AA being transferred
to the α-keto position of an α-keto acid
transamination
enzyme that adds O-GlcNac
OGT
enzyme that removes O-GlcNac
OGA
what is the outcome of the hexosamine biosynthetic pathway
O-GlcNac
